Search

Particulate matters of different aerodynamic diameters; TSP, PM10 for 24 hours were collected on quartz 47mm filter paper using Frm OMNITM Ambient Air Sampler from December 2010 to March 2011 and analyzed. The analysis of these sample collected were carried out by gravimetric, X-ray fluorescent and ion-chromatographic methods. TSP value for the observed period lies between 31.3-84.08 μg/m³ while PM10 ranges from 39.5-104.2 μg/m³. Daily carbonaceous aerosols concentration in TSP varied widely between (5.3-18.2 μg/m³) for Organic carbon (OC) and 5.6-10.2 μg/m³ for Elemental carbon (EC). Similarly in PM10 the range was from 4.8-14.1 and 3.9-10.1 μg/m³ respectively. The OC/EC ratio in the particulate matters ranges from 0.9-1.4. OC/EC ratio within 1.1 infers vehicular emission as a major source of carbonaceous aerosols in the valley. Further, among the nonionic components analyzed (K, Ca, Fe, Ti and Pb) showed highest -andCa2+ are only in few samples. Few samples of soil analyzed shows maximum of 32 elements. Variation in the concentration of ionic nonionic and carbonaceous aerosols is not related with wind pattern and its velocity. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation is the key factor driving tropospheric photochemistry. It is strongly modulated by clouds and aerosols. A quantitative understanding of the radiation field and its effect on photochemistry is thus only possible with a detailed knowledge of the interaction between clouds and radiation. The overall objective of the project INSPECTRO was the characterization of the three-dimensional actinic radiation field under cloudy conditions. This was achieved during two measurement campaigns in Norfolk (East Anglia, UK) and Lower Bavaria (Germany) combining space-based, aircraft and ground-based measurements as well as simulations with the one-dimensional radiation transfer model UVSPEC and the three-dimensional radiation transfer model MYSTIC. During both campaigns the spectral actinic flux density was measured at several locations at ground level and in the air by up to four different aircraft. This allows the comparison of measured and simulated actinic radiation profiles. In addition satellite data were used to complete the information of the three dimensional input data set for the simulation. A three-dimensional simulation of actinic flux density data under cloudy sky conditions requires a realistic simulation of the cloud field to be used as an input for the 3-D radiation transfer model calculations. Two different approaches were applied, to derive high- and low-resolution data sets, with a grid resolution of about 100m and 1 km, respectively. The results of the measured and simulated radiation profiles as well as the results of the ground based measurements are presented in terms of photolysis rate profiles for ozone and nitrogen dioxide. During both campaigns all spectroradiometer systems agreed within ±10% if mandatory corrections e.g. stray light correction were applied. Stability changes of the systems were below 5% over the 4 week campaign periods and negligible over a few days. The J(O¹D) data of the single monochromator systems can be evaluated for zenith angles less than 70°, which was satisfied by nearly all airborne measurements during both campaigns. The comparison of the airborne measurements with corresponding simulations is presented for the total, downward and upward flux during selected clear sky periods of both campaigns. The compliance between the measured (from three aircraft) and simulated downward and total flux profiles lies in the range of ±15%. [ABSTRACT FROM AUTHOR]

In September 2002, the first INSPECTRO campaign to study the influence of clouds on the spectral actinic flux in the lower troposphere was carried out in East Anglia, England. Measurements of the actinic flux, the irradiance and aerosol and cloud properties were made from four ground stations and by aircraft. The radiation measurements were modelled using the uvspec model and ancillary data. For cloudless conditions, the measurements of the actinic flux were reproduced by 1-D radiative transfer modelling within the measurement and model uncertainties of about ±10%. For overcast days, the ground-based and aircraft radiation measurements and the cloud microphysical property measurements are consistent within the framework of 1-D radiative transfer and within experimental uncertainties. Furthermore, the actinic flux is increased by between 60-100% above the cloud when compared to a cloudless sky, with the largest increase for the optically thickest cloud. Correspondingly, the below cloud actinic flux is decreased by about 55-65%. Just below the cloud top, the downwelling actinic flux has a maximum that is seen in both the measurements and the model results. For broken clouds the traditional cloud fraction approximation is not able to simultaneously reproduce the measured above-cloud enhancement and below-cloud reduction in the actinic flux. [ABSTRACT FROM AUTHOR]

The article presents comments of the manuscript about the study of ultraviolet (UV) doses to psoriasis patients during climate therapy in March 2006 in Gran Canaria, Spain. One comment refers to a disadvantage in estimating UV exposure due to personal dosimeters. Another comment refers to the uncertainty of the methods used in the study to measure UV dose.

We compare results for the UV index (UVI), the total ozone column (TOC), and the radiation modification factor (RMF, being 1 in the absence of clouds and aerosols) at four sites on the Tibetan Plateau. The results were obtained by analyzing ground measurements by multichannel moderate-bandwidth filter instruments for the period July 2008-September 2010, and radiative transfer modeling was used to aid the interpretation of the results. The highest UVI of 20.6 was measured in Tingri (28.7°N; 4335 m). For July, monthly mean UVI values were 14.5 and 12.9 in Tingri and Lhasa (29.7°N; 3683 m), respectively. Generally, the UVI levels in Tingri and Lhasa were higher than in Nagchu (31.5°N; 4510 m) and Linzhi (29.7°N; 2995 m), due to less cloud cover at the former two sites. In 2009, the annual mean UVI and RMF values were 6.8 and 0.7 for Linzhi, 8.8 and 0.92 for Lhasa, 10.5 and 0.92 for Tingri, and 6.7 and 0.7 for Nagchu. Radiative transfer simulations indicate that the latitude difference would correspond to an increase in the UVI of about 0.3 from Nagchu to Tingri; whereas, the altitude difference would correspond to a reduction of about 1.5%, implying that the observed difference is due to the difference in cloud cover. The annual mean TOC values were found to be 260-264 Dobson units (DU) in Lhasa, Linzhi, and Nagchu, and 252 DU in Tingri. TOC values in Lhasa were found to agree within 3% with those derived from Ozone Monitoring Instrument (OMI) measurements.

Irradiation in the ultraviolet wavelength range is found to be up to 50% lower in the European summer compared to sites with comparable latitudes in New Zealand. We have developed a method to quantitatively attribute the causes for such differences between sites by analysis of spectra. We conclude that these large differences are caused mainly by differences in total ozone, cloudiness, aerosol loading and Sun-Earth separation. The relative contribution of clouds varies from year to year and it is site dependent. Averaged over several years we find a strong latitudinal gradient of the cloud impact within Europe, with much less cloud attenuation in southern Europe. Due to the differences in total ozone and aerosol loading, the UV-B levels are generally lower in Europe compared to New Zealand. It is likely that inter-hemispheric differences will change in coming decades due to a combination of changes in ozone concentrations, air pollution and cloudiness as a result of climate change. However, since the future evolution of these major parameters is highly uncertain, the magnitude and even the sign of such changes are not known yet.

The diurnal and annual variability of solar UV radiation in Europe is described for different latitudes, seasons and different biologic weighting functions. For the description of this variability under cloudless skies the widely used one-dimensional version of the radiative transfer model UVSPEC is used. We reconfirm that the major factor influencing the diurnal and annual variability of UV irradiance is solar elevation. While ozone is a strong absorber of UV radiation its effect is relatively constant when compared with the temporal variability of clouds. We show the significant role that clouds play in modifying the UV climate by analyzing erythemal irradiance measurements from 28 stations in Europe in summer. On average, the daily erythemal dose under cloudless skies varies between 2.2 kJ m(-2) at 70 degrees N and 5.2 kJ m(-2) at 35 degrees N, whereas these values are reduced to 1.5-4.5 kJ m(-2) if clouds are included. Thus clouds significantly reduce the monthly UV irradiation, with the smallest reductions, on average, at lower latitudes, which corresponds to the fact that it is often cloudless in the Mediterranean area in summer.

A measurement scheme and an algorithm have been developed to retrieve global irradiance ultraviolet solar spectra (290-400 nm) at a sampling rate of 0.5 Hz. The algorithm combines spectral irradiance measurements performed with a slow (a few minutes) scanning spectroradiometer (Optronic Model OL752) and a moderate bandwidth multichannel radiometer (Biospherical ground-based ultraviolet radiometer Model 541). The filter radiometer instrument allows for continuous observations of global UV radiation at five channels (approximately 10-nm bandwidth), performed simultaneously with spectral measurements. Information about changing cloud conditions during a spectral scan was retrieved from filter measurements and applied to spectral data, hence estimated spectra without cloud variations could be constructed. The quality of the estimated spectra depends on data quality from both instruments. The method works well in all kinds of weather conditions, as long as the Sun is above the horizon and none of the instruments are hampered by measurement errors.

The intracellular pH of the Gram-positive skin bacterium Propionibacterium acnes was determined using the pH-sensitive fluorescent probe 2',7'-bis-(2-carboxyethyl)-5-(and-6)carboxyfluorescein (BCECF). The probe was introduced into the bacteria using the membrane-permeable acetoxymethyl ester BCECF-AM. The intracellular pH of the bacteria was determined by establishing a relation between the fluorescence ratio 505/450 and pH using the ionophore nigericin. To verify the intracellular pH determined using BCECF, the results were compared with those obtained using 31P-NMR spectroscopy. The effects of different external pH values and glucose addition upon the intracellular pH were examined using BCECF and 31P-NMR. Good correlation was obtained between the two techniques. Propionibacterium acnes maintained a pH gradient, inside alkaline, in the external pH range 5.0-7.4, which inverted when the pH was > 7.5. At external pH > or equal to 8.5, the intracellular pH was close to the external pH. Glucose exposure did not affect the intracellular pH. Rapid, transient intracellular acidification and alkalinization brought about using NaHCO3 and NH4Cl, respectively, could be detected using BCECF. A limitation encountered when using BCECF was BCECF leakage, which could significantly affect the results if not taken into account.

The effect of low level laser (GaAs) on lateral epicondylitis was investigated in a double-blind, randomized, controlled study. Thirty patients were assigned equally to a laser (n = 15) or a placebo laser (n = 15) group. All patients received eight treatments and were evaluated subjectively and objectively before, at the end of, and four weeks after treatment. Patients also completed a follow-up questionnaire on an average of five to six months after treatment. A significant improvement in the laser compared to the placebo group was found on visual analog scale (p = 0.02) and grip strength (p = 0.03) tests four weeks after treatment. In this study low level laser therapy was shown to have an effect over placebo; however, as a sole treatment for lateral epicondylitis it is of limited value. Further studies are needed to evaluate the reliability of our findings and to compare laser to other established treatment methods.

Electron microscopy showed that electron-dense granules accumulated in Propionibacterium acnes in larger amounts when the bacteria were grown on a phosphate-rich medium. X-ray microanalysis demonstrated that the granules contained mostly phosphorus and potassium, indicating that the cells contained polyphosphate granules. When cells were grown on a complex Bacto-agar medium, the amount and the size of the polyphosphate granules were reduced. Polyphosphate was also detected with 31P nuclear magnetic resonance (31P-NMR). Of the polyphosphates observed with 31P-NMR, 20% seemed to be located outside the cell membrane. Broad-band near-ultraviolet irradiation (emission maximum 366 nm) corresponding to doses that killed 37% of the cells increased the amount of polyphosphate in cells grown on the phosphate-rich medium. The fluorescent chromophore 4',6-diamidino-2-phenylindole (DAPI) shifted the fluorescence emission from 478 to 538 nm when bound to polyphosphate and excited at 340 nm. DAPI was used to detect polyphosphates generated after near-ultraviolet irradiation of the cells. Nonirradiated cells showed no increased fluorescence at 538 nm, indicating no polyphosphate is presented in the cells. We conclude that DAPI did not have "access" to the intracellular polyphosphate as long as the cells were not light damaged. This observation is important for the interpretation of near-UV damage to cells.

Suspensions of Propionibacterium acnes were UV irradiated and the induced radicals were measured at 77 K by electron spin resonance (ESR) spectrometry. Two types of radical were formed during irradiation and stabilized in the frozen suspensions. The relative yield of each radical was studied as a function of irradiation wavelength. The first radical, which was a singlet with a peak-to-peak width of 20 G, was insensitive to the deoxygenation of the samples and to the exchange of solvent water by heavy water. The action spectrum was similar to the absorption spectrum of NADPH. The second type of radical was not formed in deoxygenated samples and the shape of the ESR spectrum was characteristic of the superoxide radical. This radical was only formed at wavelengths below 340 nm.

Photodestruction of Propionibacterium acnes was investigated by broad-band near-ultraviolet light. The inactivation of the bacteria was found to be oxygen dependent, and without O2 practically no photoinactivation occurred. D2O caused an increased inactivation (D10 = 5 kJ/m2 in D2O as compared to D10 = 11 kJ/m2 in normal water). Decreased temperature during illumination increased the ability to form colonies. The results are compared with corresponding results for other types of cells and the destruction mechanism is discussed.

The polyphosphate component in 31P NMR spectra of the Gram-positive Propionibacterium acnes increased after hyperthermia treatment. The cells were exposed to temperatures in the interval from 15 degrees C to 45 degrees C. The amount of polyphosphate increased with increasing temperature. There were no temperature induced changes in the other phosphorous components seen in the spectra with exception of a decrease in ATP for higher temperatures. The increase in polyphosphates was less than that obtained from cells irradiated by near ultra-violet light.